I'm good with just adding an example to the docs, along the lines of Paul's del_rw.  I think it would be better to use a more conservative example though, something like:

   def readonly_handler(rm_func, path, exc_info):
       if issubclass(exc_info[0], PermissionError) and exc_info[1].winerror == 5:
           os.chmod(path, stat.S_IWRITE)
           return rm_func(path)
       raise exc_info[1]